1. Field of the Invention
The present invention relates to a portable electronic apparatus including an electronic camera apparatus such as an imaging device-integrated lens interchangeable electronic camera apparatus and a camera head unit, and particularly to a cooling structure of the imaging device module.
2. Description of the Related Art
Generally, when an imaging device which is an electronic component and Central Processing Unit (CPU) constituting a control circuit are incorporated into this kind of portable electronic apparatus, there is a need for not only adopting thermal control but also ensuring dust control. As to the thermal control, when the dust control is improved, a temperature of the electronic component rises to increase a noise level, which causes image quality to be deteriorated in the case of the electronic camera apparatus. Therefore, recently the thermal control has become a large problem because of the increased performance of the imaging device or CPU.
For example, Jpn. Pat. Appln. KOKAI Publication Nos. 02-143152, 2006-332894, and 2006-174226 disclose a liquid-cooled radiation structure and an air-cooled radiation structure.
In the liquid-cooled radiation structure disclosed in Jpn. Pat. Appln. KOKAI Publication No. 02-143152, a cooling plate is brought into contact with a surface of an integrated circuit element mounted on a circuit board, and cooling water is supplied to a fine cooling medium flow passage to water-cool the cooling plate. A contact area is increased to obtain good thermal conductivity by disposing a thermal-conductive variable shape substance such as a compound having excellent thermal conductivity in a thermal coupling portion located between the cooling plate and the integrated circuit element.
Specifically, many integrated circuit elements are mounted on one surface side of a circuit board such as a ceramic plate. In a liquid cooling module disposed in the circuit board, the thermal-conductive variable shape substance such as the compound having excellent thermal conductivity is interposed between the surface of the integrated circuit element and the cooling plate to which the cooling medium is supplied through the cooling medium flow passage, and good thermal coupling is obtained between the cooling plate and the integrated circuit element by a spring force of a spring. Liquid supplying means includes a cooling medium supply pipe connected to the cooling medium passage, an on-off valve, and a mechanical pump.
Jpn. Pat. Appln. KOKAI Publication No. 2006-332894 discloses an air-cooled imaging apparatus including a body-side mount incorporated into a main body structure in a camera body to support an imaging lens, a shutter disposed along an optical axis in an opening of the main body structure, and an imaging unit. The imaging unit includes an imaging device fixing plate fixed to and supported by the main body structure, an optical lowpass filter, a protective glass, and a bear chip imaging device. In the imaging device, the imaging device fixing plate constituting a radiation plate is bonded and fixed to a surface on non-imaging surface side to ensure a distance in an optical axis direction from the surface of the body-side mount to the imaging surface (photoelectric conversion surface) of the imaging device. The heat generated by driving the imaging device is radiated through the imaging device fixing plate to suppress the temperature rise.
Jpn. Pat. Appln. KOKAI Publication No. 2006-174226 discloses an imaging device swing-type imaging unit with an image stabilizing function, wherein the imaging device including a package, a lead terminal, and a cover glass is mounted on a circuit board, and an opening provided in the circuit board abuts on a heat absorbing surface of a cooling element such as a Peltier element while a flexible sheet is disposed in the backside of the package. A small radiation member is disposed between the backside of the package and the heat absorbing surface of the cooling element, a large radiation member is disposed on a chassis side, and the small radiation member and the large radiation member are thermally coupled by a heat transfer member.